Work out concrete footing volume instantly with clear inputs, formula shown and shareable results.
Pad footing concrete is the plan area times the thickness for each footing. Excavation is always larger: 150 mm of working space on each side lets the shuttering be placed and stripped, and 50 mm of blinding gives a clean base to fix reinforcement on.
Footing volume
V = length x width x thickness x count
Excavation
V exc = (L + 0.3) x (W + 0.3) x (T + 0.05) x count
V = length x width x thickness x count. Pad footing concrete is the plan area times the thickness for each footing.
Blinding stops soil contaminating the concrete cover and gives a level surface to set bar spacers on, which is what actually delivers the specified cover to the steel.
This calculator takes 4 inputs: Footing length, Footing width, Footing thickness, Number of footings. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.